CN111640403B - Liquid crystal display device and method for adjusting common voltage - Google Patents

Liquid crystal display device and method for adjusting common voltage Download PDF

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CN111640403B
CN111640403B CN202010492214.0A CN202010492214A CN111640403B CN 111640403 B CN111640403 B CN 111640403B CN 202010492214 A CN202010492214 A CN 202010492214A CN 111640403 B CN111640403 B CN 111640403B
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common voltage
liquid crystal
voltage
crystal capacitor
source
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CN111640403A (en
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朱威武
张婷婷
王腾
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Wuhan China Star Optoelectronics Technology Co Ltd
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Wuhan China Star Optoelectronics Technology Co Ltd
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3614—Control of polarity reversal in general
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/13338—Input devices, e.g. touch panels
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0412—Digitisers structurally integrated in a display
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3696—Generation of voltages supplied to electrode drivers

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  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Computer Hardware Design (AREA)
  • General Engineering & Computer Science (AREA)
  • Nonlinear Science (AREA)
  • Human Computer Interaction (AREA)
  • Mathematical Physics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Liquid Crystal Display Device Control (AREA)

Abstract

The invention provides a liquid crystal display device and a method for adjusting a common voltage, which solve the problem of abnormal pictures by calculating the optimal common voltage according to the electrical characteristics of two ends of a liquid crystal capacitor when the source voltage is respectively positive and negative after judging that the common voltage needs to be adjusted, ensuring that the absolute value of the difference between the source voltage in the positive polarity and the optimal common voltage is equal to the absolute value of the difference between the source voltage in the negative polarity and the optimal common voltage, and controlling the output of the common voltage according to the optimal common voltage. Further, the adjustment of the common voltage can be performed during the idle time of each frame, so that the optimal common voltage can be adjusted from time to time during the display of the display panel.

Description

Liquid crystal display device and method for adjusting common voltage
Technical Field
The present invention relates to the field of display technologies, and in particular, to a liquid crystal display device and a method for adjusting a common voltage.
Background
In a liquid crystal display device, when liquid crystal molecules are operated in an electric field of the same polarity for a long time, the liquid crystal molecules are easily polarized to cause permanent destruction, and the screen of the liquid crystal display device is abnormal.
Referring to FIG. 1, FIG. 1 shows a source voltage V applied across liquid crystal moleculesSAnd a common voltage VCSchematic representation of (a). To ensure the display effect, the source voltage VSWhen it is positive (at this time, the source voltage V)SGreater than the common voltage VC) Source voltage V ofSAnd a common voltage VCVoltage difference Δ V of+Required and source voltage VSAt negative polarity (at this time, the source voltage V)SLess than the common voltage VC) Source voltage V ofSAnd a common voltage VCVoltage difference Δ V of-Similarly, an optimum common voltage is usually found in a production line and is written into the lcd device by One Time Programming (OTP). However, in the actual production of the liquid crystal display device, there may be various factors such as charge residue and temperature variation, which may cause the written common voltage not to be actuallyThe optimum common voltage is shifted from the optimum common voltage, and the problem of image sticking or flickers (flickers) occurs on the screen of the liquid crystal display device. Therefore, it is necessary to provide a liquid crystal display device and a method for adjusting a common voltage to solve the problems of the prior art.
Disclosure of Invention
The invention aims to provide a liquid crystal display device and a method for adjusting a common voltage, so as to solve the problem of abnormal pictures.
To achieve the above object, a first aspect of the present invention provides a liquid crystal display device comprising:
the display panel comprises a plurality of pixels which are arranged in an array mode, each pixel is provided with a pixel electrode and a liquid crystal capacitor, and the pixel electrode forms one part of the liquid crystal capacitor; and
a driver integrated circuit, comprising:
the source electrode voltage driver is connected with one end of the liquid crystal capacitor and used for outputting source electrode voltage to one end of the liquid crystal capacitor;
the common voltage driver is connected with the other end of the liquid crystal capacitor and used for outputting a common voltage to the other end of the liquid crystal capacitor;
the detection module is connected with the liquid crystal capacitor and used for detecting the electrical characteristics of two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity;
the judging module is connected with the detecting module and used for judging whether the common voltage needs to be adjusted or not according to the electrical characteristics of the two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity, and transmitting an adjusting signal if the common voltage needs to be adjusted;
a common voltage calculation module connected to the determination module, wherein when the common voltage calculation module receives the adjustment signal, an optimal common voltage is calculated according to electrical characteristics of both ends of the liquid crystal capacitor at positive and negative polarities of the source voltage, so that an absolute value of a difference between the positive polarity of the source voltage and the optimal common voltage is equal to an absolute value of a difference between the negative polarity of the source voltage and the optimal common voltage; and
and the common voltage adjusting module is connected with the common voltage calculation module and the common voltage driver and used for controlling the common voltage driver to output the common voltage according to the optimal common voltage after receiving the optimal common voltage.
Optionally, the determining module determines whether an absolute value of a difference between the positive polarity of the source voltage and the common voltage is equal to an absolute value of a difference between the negative polarity of the source voltage and the common voltage according to a voltage difference between two ends of the liquid crystal capacitor when the source voltage is positive polarity and negative polarity, respectively, so as to determine whether the common voltage needs to be adjusted.
Further, if the absolute value of the difference between the source voltage with positive polarity and the common voltage is not equal to the absolute value of the difference between the source voltage with negative polarity and the common voltage, the common voltage needs to be adjusted.
Alternatively, the common voltage calculation module calculates a common voltage such that an absolute value of a difference between the positive polarity of the source voltage and the positive polarity of the common voltage is equal to an absolute value of a difference between the negative polarity of the source voltage and the common voltage, based on a voltage difference between the positive polarity of the source voltage and the negative polarity of the source voltage between the two ends of the liquid crystal capacitor, and the common voltage at this time is the optimal common voltage.
Optionally, the determining module is configured to: and Q is C Δ V, the charge quantity stored by the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity is obtained by utilizing the voltage difference of two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity, and whether the charge quantity stored by the liquid crystal capacitor is equal when the source voltage is respectively positive polarity and negative polarity is judged to judge whether the common voltage needs to be adjusted or not.
Further, if the amounts of charges stored at the two ends of the liquid crystal capacitor when the source voltages are positive and negative, respectively, are not equal, the common voltage needs to be adjusted.
Optionally, the detecting module is further configured to detect a time when the source current charges the liquid crystal capacitor when the source voltage at the two ends of the liquid crystal capacitor is positive and negative respectively, and the common voltage calculating module is configured to: q ═ ISt, when the source voltage is respectively positive polarity and negative polarity, respectively calculating the charge amount stored by two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity by controlling the source voltage driver to output the same source current, and according to the detected time for charging the liquid crystal capacitor by the source current, and adjusting the common voltage according to the stored charge amount to obtain the optimal common voltage, wherein Q is the charge amount stored by the liquid crystal capacitor, I is the charge amount stored by the liquid crystal capacitorSIs the source current, and t is the time for the source current to charge the liquid crystal capacitor.
Further, the display panel is a touch display panel having a plurality of touch electrodes, and the driving integrated circuit transmits the common voltage to the plurality of touch electrodes through a plurality of conductive traces.
Further, the common voltage adjusting module adjusts the common voltage during an idle time of each frame.
A second aspect of the invention provides a method of regulating a common voltage, the method comprising the steps of:
applying a source voltage to one end of a liquid crystal capacitor in each of a plurality of pixels constituting a display panel and applying a common voltage to the other end;
detecting the electrical characteristics of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity;
judging whether the common voltage needs to be adjusted according to the electrical characteristics of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity, if so, executing the following steps, otherwise, ending the method for adjusting the common voltage;
calculating an optimum common voltage such that an absolute value of a difference between the source voltage at the positive polarity and the optimum common voltage is equal to an absolute value of a difference between the source voltage at the negative polarity and the optimum common voltage, based on electrical characteristics of the liquid crystal capacitor at the positive polarity and the negative polarity, respectively; and
and controlling the output of the common voltage according to the optimal common voltage.
The invention calculates the optimal common voltage according to the electrical characteristics of the two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity after judging that the common voltage needs to be adjusted, so that the absolute value of the difference between the source voltage in the positive polarity and the optimal common voltage is equal to the absolute value of the difference between the source voltage in the negative polarity and the optimal common voltage, and controls the output of the common voltage according to the optimal common voltage, thereby solving the problem of abnormal pictures. Furthermore, the adjustment of the common voltage can be executed in the idle time of each frame, and the time sequence of the common electrode is set and adjusted according to the requirement, so that the optimal common voltage is adjusted in the display process of the display panel at any time.
Drawings
FIG. 1 is a schematic diagram of a source voltage and a common voltage applied across liquid crystal molecules.
Fig. 2 is a block diagram of an lcd device according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of a driving circuit of a display panel according to an embodiment of the invention.
Fig. 4 is a schematic view of a display panel having a plurality of touch electrodes according to an embodiment of the invention.
Fig. 5 is a flowchart of a method for adjusting a common voltage according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 2 and fig. 3, fig. 2 is a block diagram of a liquid crystal display device 20 according to an embodiment of the invention, and fig. 3 is a diagram of a driving circuit of a display panel 22 according to an embodiment of the invention. The lcd device 20 includes a driving ic 21 and a display panel 22, wherein the driving ic 21 includes an active voltage driver 211, a common voltage driver 212, a detection module 213, a determination module 214, a common voltage calculation module 215, and a common voltage adjustment module 216, the display panel 22 includes a plurality of pixels 221 arranged in an array, each pixel 221 has a liquid crystal capacitor C connected thereto respectivelyLPixel electrodes (not shown) and common electrodes (not shown) at both ends, to which source voltages V are respectively inputSAnd a common voltage VC. It should be noted that the driving integrated circuit 21 and the display panel 22 in fig. 2 further include other elements, and this embodiment only shows some elements to illustrate the inventive emphasis of the present invention, which should not be construed as limiting the present invention.
In one embodiment, the source voltage driver 211, the common voltage driver 212, the detecting module 213, the determining module 214, the common voltage calculating module 215, and the common voltage adjusting module 216 may be integrated into the same functional module, or only some of these modules may be integrated into the same functional module. In order to more clearly describe the present invention, the present embodiment describes these modules according to their functions.
In one embodiment, the method of driving the liquid crystal molecules to deflect at least comprises: (1) as shown in fig. 1, the source voltage VSWith time variation, common voltage VCIs a constant value; (2) the source voltage and the common voltage both vary with time (not shown), and the present invention is applicable to the driving method described above or the driving method that can be realized by those skilled in the art, and the present invention is not limited thereto.
In the present embodiment, when the source voltage driver 211 outputs the source voltage VSTo the liquid crystal capacitor CLThe common voltage driver 212 outputs a common voltage VCTo the liquid crystal capacitor CLAt the other end of (2), the detection module 213 detects the liquid crystal capacitance CLTwo ends are at source voltage VSThe electrical characteristics are positive and negative, respectively.
Specifically, when the source voltage V is appliedSWhen it is positive (at this time, the source voltage V)SGreater than the common voltage VC) Detecting the source voltage V at this timeSAnd a common voltage VCValue of (V)S+And VC+) When the source voltage V isSAt negative polarity (at this time, the source voltage V)SLess than the common voltage VC) Detecting the source voltage V at this timeSAnd a common voltage VCValue of (V)S－And VC－). If the liquid crystal molecules are driven to deflect in such a way that the source voltage V isSWith time variation, common voltage VCIs a constant value, then VC+＝VC－V if the liquid crystal molecules are driven to deflect in such a manner that both the source voltage and the common voltage vary with timeC+≠VC－. It is to be understood that the present invention is not limited to the structure of the detection module 213, and the source voltage V is described in the specificationSAt positive polarity and a common voltage VCThe difference "(or the like) can be understood as" the source voltage V at positive polarityS+And a common voltage V in the positive polarityC+The difference "is not listed here.
Further, the determining module 214 determines the liquid crystal capacitance according to CLTwo ends are at source voltage VSThe electrical characteristics of the positive polarity and the negative polarity respectively, and whether the common voltage needs to be adjusted is judged.
In one embodiment, the determining module 214 determines the V detected by the detecting module 213S+、VC+、VS－、VC－Calculating the liquid crystal capacitance CLTwo ends are at source voltage VSVoltage difference (Δ V) between positive and negative polarities+And Δ V-) If | Δ V+|＝|ΔV-I.e. VS+–VC+|＝|VS-–VC-I, the common voltage V at this timeCFor optimum, common voltage VCWithout adjustment, if | Δ V+|≠|ΔV-I.e. VS+–VC+|≠|VS-–VC-I, the common voltage V at this timeCNot optimally, the common voltage VCAdjustments are required.
In one embodiment, the determining module 214 determines the relationship: q ═ C Δ V, V detected by detection module 213S+、VC+、VS－、VC－Calculating the liquid crystal capacitance CLTwo ends are at source voltage VSVoltage difference (Δ V) between positive and negative polarities+And Δ V-) To further obtain the liquid crystal capacitance CLAt source voltage VSThe amount of charge (Q) stored in the case of positive and negative polarity, respectively+And Q-) Wherein Q is a liquid crystal capacitor CLThe amount of stored charge, C, being the liquid crystal capacitance CLΔ V is the liquid crystal capacitance CLVoltage difference of (c). Due to the liquid crystal capacitance CLAnd output source supply VSPixel electrode and output common power supply VCHas a positive area and a distance such that the liquid crystal capacitance C isLThe capacitance C is constant during the display process of the liquid crystal panel 22, so that the capacitance C can be determined according to the liquid crystal capacitance CLTwo ends are at source voltage VSVoltage difference (Δ V) between positive and negative polarities+And Δ V-) To obtain the liquid crystal capacitance CLTwo ends are at source voltage VSThe amount of charge (Q) stored in the case of positive and negative polarity, respectively+And Q-). If Q+＝Q-Indicates the common voltage V at this timeCFor optimum, common voltage VCNo adjustment is required, if Q+≠Q-Indicates the common voltage V at this timeCNot optimally, the common voltage VCAdjustments are required.
If the determination module 214 determines that the common voltage V is lower than the predetermined valueCIf the adjustment is needed, the determining module 214 sends an adjustment signal to the common voltage calculating module 215.
Further, the common voltage calculation module 215 is connected to the determination module 214Then, when the common voltage operation module 215 receives the adjustment signal, it will operate according to the liquid crystal capacitance CLTwo ends are at source voltage VSCalculating the optimum common voltage V for the electrical characteristics of positive and negative polarityCB(or is VCB-And VCB-) So that the source voltage V isSAt positive polarity and the optimum common voltage VBThe absolute value of the difference with the source voltage VSAt negative polarity and optimum common voltage VBThe absolute values of the differences being equal, i.e. | VS+–VCB+|＝|VS-–VCB-L. For example, the optimum common voltage VBMay be a source voltage VSValue (V) at positive polarity and negative polarityS+And VS-) Half of the sum of (i.e. V)CB＝(VS++VS-) /2) the algorithm is applied to the source voltage VSWith time variation, common voltage VCA constant value driving mode (as shown in figure 1); alternatively, the source voltage V can be adjustedSValue (V) at positive polarity and negative polarityS+And VS-) Half of the sum of (i.e., (V))S++VS-) /2) set to the optimum common voltage VCBSo that the optimum common voltage V isCBThe difference between the positive polarity and the negative polarity and the center is the same value, and the calculation method is suitable for a driving method that the source voltage and the common voltage change along with time.
In one embodiment, the common voltage calculation module 215 calculates the voltage according to the V detected by the detection module 213S+、VC+、VS－、VC－Calculating the liquid crystal capacitance CLAt source voltage V acrossSVoltage difference (Δ V) between positive and negative polarities+And Δ V-) Calculating to make the source voltage VSAt positive polarity and a common voltage VCThe absolute value of the difference with the source voltage VSAt negative polarity and a common voltage VCCommon voltage V with equal absolute value of differenceCAt this time, the common voltage VCI.e. the optimum common voltage VCB。
In one embodiment, the detection module 214 is further configured to detectLiquid crystal capacitor CLAt source voltage V acrossSSource current I with positive and negative polarity respectivelySTo liquid crystal capacitor CLThe charging time t. The common voltage operation module 215 is according to the relation: q ═ ISt at source voltage VSWhen the voltage is positive and negative, the source voltage driver 211 is controlled to output the same source current ISAnd based on the detected source current ISTo liquid crystal capacitor CLCalculating the charging time t to obtain the liquid crystal capacitor CLAt source voltage V acrossSThe amount of charge (Q) stored in the case of positive and negative polarity, respectively+And Q-) And based on it, determining the liquid crystal capacitance CLAt source voltage VSThe quantity Q of charge stored in positive polarity+And a liquid crystal capacitor CLThe amount of charge Q stored when the source voltage VS is negative-The same charging time t is used to adjust the common voltage VCThe charging time t at this time can be further determined according to the following relation: q ═ ISt ═ C Δ V to derive the optimum common voltage VCB。
Further, the common voltage adjusting module 216 is connected to the common voltage calculating module 215 and the common voltage driver 212, and the common voltage adjusting module 216 receives the optimal common voltage VCBThen controls the common voltage driver 212 to make it according to the optimum common voltage VCBTo output a common voltage VCFurther, the problems of image sticking or flickers in the picture are solved.
Referring to fig. 4, fig. 4 is a schematic view of a display panel 22 having a plurality of touch electrodes 223 according to an embodiment of the invention. The driving integrated circuit 21 is disposed at one end of the display panel 22, and the driving integrated circuit drives the common voltage V through a plurality of conductive traces 222CTo the plurality of touch electrodes 223. The display panel 22 of the present invention may be a touch display panel, the touch electrode 223 of the touch display panel may be used as a common electrode, the touch electrode 223 is densely distributed on the display panel 22, and the present invention may apply the common voltage V on the densely distributed touch electrode 223CAnd (6) adjusting.
In the present embodiment, the common voltage adjustment module 216 performs the above-mentioned operation on the common voltage VCThe adjustment of (1) can be performed during the idle (blanking) time of each frame, and the adjustment of the common voltage V is set according to the requirementsCTo adjust the optimum common voltage V from time to time during the display of the display panel 22 (e.g., once every 10 frames)CB。
Referring to fig. 5, and in conjunction with the above description and drawings, fig. 5 is a flowchart of a method for adjusting a common voltage according to an embodiment of the present invention. The method comprises the following steps:
s10: a liquid crystal capacitor C in each of a plurality of pixels 221 constituting the display panel 22LOne terminal of which is applied with a source voltage VSThe other end of the common voltage V is appliedC。
S20: detecting liquid crystal capacitance CLAt source voltage VSThe electrical characteristics are positive and negative, respectively.
S30: according to the liquid crystal capacitance CLAt source voltage VSThe electrical characteristics of positive polarity and negative polarity respectively, and whether the common voltage V needs to be adjustedC. If so, step S40 is executed, otherwise, the method for adjusting the common voltage is ended.
S40: according to the liquid crystal capacitance CLAt source voltage VSCalculating the optimum common voltage V for the electrical characteristics of positive and negative polarityCBWhich makes the source voltage VSAt positive polarity and the optimum common voltage VCBThe absolute value of the difference with the source voltage VSAt negative polarity and optimum common voltage VCBThe absolute values of the differences are equal.
S50: according to the optimum common voltage VCBControlling the common voltage VCTo output of (c).
For more details, reference may be made to the above description of the liquid crystal display device 20, which is not repeated herein.
Although the present invention has been described with reference to the preferred embodiments, it is to be understood that the present invention is not limited to the disclosed embodiments, and that various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope of the present invention.

Claims (9)

1. A liquid crystal display device comprising:
the display panel comprises a plurality of pixels which are arranged in an array mode, each pixel is provided with a pixel electrode and a liquid crystal capacitor, and the pixel electrode forms one part of the liquid crystal capacitor; and
a driver integrated circuit, comprising:
the source electrode voltage driver is connected with one end of the liquid crystal capacitor and used for outputting source electrode voltage to one end of the liquid crystal capacitor;
the common voltage driver is connected with the other end of the liquid crystal capacitor and used for outputting a common voltage to the other end of the liquid crystal capacitor;
the detection module is connected with the liquid crystal capacitor and used for detecting the electrical characteristics of two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity;
the judging module is connected with the detecting module and used for judging whether the common voltage needs to be adjusted or not according to the electrical characteristics of the two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity, and transmitting an adjusting signal if the common voltage needs to be adjusted;
a common voltage calculation module connected to the determination module, wherein when the common voltage calculation module receives the adjustment signal, an optimal common voltage is calculated according to electrical characteristics of both ends of the liquid crystal capacitor at positive and negative polarities of the source voltage, so that an absolute value of a difference between the positive polarity of the source voltage and the optimal common voltage is equal to an absolute value of a difference between the negative polarity of the source voltage and the optimal common voltage; and
a common voltage adjusting module connected to the common voltage calculating module and the common voltage driver for controlling the common voltage driver to output the common voltage according to the optimal common voltage after receiving the optimal common voltage,
the method is characterized in that: the detection module is further configured to detect a time when the source current charges the liquid crystal capacitor when the source voltage at the two ends of the liquid crystal capacitor is positive and negative, respectively, and the common voltage operation module is configured to: q ═ ISt, when the source voltage is respectively positive polarity and negative polarity, respectively calculating the charge amount stored by two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity by controlling the source voltage driver to output the same source current, and according to the detected time for charging the liquid crystal capacitor by the source current, and adjusting the common voltage according to the stored charge amount to obtain the optimal common voltage, wherein Q is the charge amount stored by the liquid crystal capacitor, I is the charge amount stored by the liquid crystal capacitorSIs the source current, and t is the time for the source current to charge the liquid crystal capacitor.
2. The liquid crystal display device according to claim 1, wherein: the judging module judges whether the absolute value of the difference between the positive polarity of the source voltage and the common voltage is equal to the absolute value of the difference between the negative polarity of the source voltage and the common voltage according to the voltage difference between the positive polarity of the source voltage and the negative polarity of the source voltage at the two ends of the liquid crystal capacitor so as to judge whether the common voltage needs to be adjusted.
3. The liquid crystal display device according to claim 2, wherein: if the absolute value of the difference between the source voltage with positive polarity and the common voltage is not equal to the absolute value of the difference between the source voltage with negative polarity and the common voltage, the common voltage needs to be adjusted.
4. The liquid crystal display device according to claim 1, wherein: the common voltage calculation module calculates a common voltage such that an absolute value of a difference between the source voltage at the positive polarity and the common voltage at the negative polarity is equal to an absolute value of a difference between the source voltage at the negative polarity and the common voltage, based on a voltage difference between the two ends of the liquid crystal capacitor at the positive polarity and the negative polarity, respectively, and the common voltage at this time is the optimum common voltage.
5. The liquid crystal display device according to claim 1, wherein: the judging module is used for judging whether the relation is as follows: and Q is C Δ V, the charge quantity stored by the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity is obtained by utilizing the voltage difference of two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity, and whether the charge quantity stored by the liquid crystal capacitor is equal when the source voltage is respectively positive polarity and negative polarity is judged to judge whether the common voltage needs to be adjusted or not.
6. The liquid crystal display device according to claim 5, wherein: if the charge amounts stored at the two ends of the liquid crystal capacitor when the source voltage is respectively positive and negative are not equal, the common voltage needs to be adjusted.
7. The liquid crystal display device according to claim 1, wherein: the display panel is a touch display panel and is provided with a plurality of touch electrodes, and the driving integrated circuit transmits the common voltage to the touch electrodes through a plurality of conductive wires.
8. The liquid crystal display device according to claim 1, wherein: the common voltage adjusting module adjusts the common voltage during an idle time of each frame.
9. A method of adjusting a common voltage, the method comprising the steps of:
applying a source voltage to one end of a liquid crystal capacitor in each of a plurality of pixels constituting a display panel and applying a common voltage to the other end;
detecting the electrical characteristics of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity;
judging whether the common voltage needs to be adjusted according to the electrical characteristics of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity, if so, executing the following steps, otherwise, ending the method for adjusting the common voltage;
detecting the time for which the source current charges the liquid crystal capacitor when the source voltage at the two ends of the liquid crystal capacitor is respectively positive and negative, according to the relation: q ═ ISt, when the source voltage is respectively positive polarity and negative polarity, respectively outputting the same source current, respectively calculating the charge amount stored by the two ends of the liquid crystal capacitor when the source voltage is respectively positive polarity and negative polarity according to the detected time of charging the liquid crystal capacitor by the source current, respectively, and adjusting the common voltage according to the stored charge amount to obtain the optimal common voltage, so that the absolute value of the difference between the source voltage in positive polarity and the optimal common voltage is equal to the absolute value of the difference between the source voltage in negative polarity and the optimal common voltage, wherein Q is the charge amount stored by the liquid crystal capacitor, I is the charge amount stored by the liquid crystal capacitor, and I is the charge amount stored by the liquid crystal capacitorSIs a source current, t is a time for the source current to charge the liquid crystal capacitor; and
and controlling the output of the common voltage according to the optimal common voltage.
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